Nataliia N.

I migrate legacy systems to Java microservices without downtime — and keep your data consistent while old and new systems run side by side. I'm a hands-on backend architect with 14+ years of Java (plus Python) in fintech, commerce, and telecom. I design the architecture and write the code myself — from requirements and API design to production rollout. What I've delivered: • Zero-downtime migration for a major US pharmaceutical distributor: replaced legacy modules with Java microservices, with Kafka-based bidirectional data sync (CDC + application events) during parallel operation • Consumer-credit platform at a digital bank: cut production incidents from 4–5/day to 2–3/month; introduced the transactional outbox pattern for reliable Kafka messaging with the risk system • Legacy performance fix: rewrote a record-by-record flow as set-based SQL — from 4 hours to 2 minutes • Telecom automation: integrated Microsoft Teams Telephony and national registries, automating 6.5 of 8 manual process steps for ~50 resellers • Python SDK for ML teams: test coverage from 45% to 90% in 6 months How I can help: • Break a monolith into services — or tell you honestly that it shouldn't be broken yet • Keep data in sync between old and new systems during migration (Kafka, CDC, outbox) • Stabilize a fragile production system: frequent incidents, flaky tests, missing logs • Architecture review or technical discovery before a major rebuild • Hands-on feature work on Java/Spring Boot or Python codebases Stack: Java 17+, Spring Boot 3, Kafka, PostgreSQL, Liquibase, Python, Docker, AWS, Azure Full overlap with US Eastern business hours, plus afternoons in Europe. I communicate clearly, document decisions, and don't disappear mid-project. Send me a short description of your system and what's hurting — I'll tell you honestly whether I'm the right fit.